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#!/usr/bin/python
# sql2dot.py
#
# Creates table graphics by parsing SQL table DML commands and
# generating DOT language output.
#
# Adapted from a post at https://energyblog.blogspot.com/2006/04/blog-post_20.html.
#
sampleSQL = """
create table student
(
student_id integer primary key,
firstname varchar(20),
lastname varchar(40),
address1 varchar(80),
address2 varchar(80),
city varchar(30),
state varchar(2),
zipcode varchar(10),
dob date
);
create table classes
(
class_id integer primary key,
id varchar(8),
maxsize integer,
instructor varchar(40)
);
create table student_registrations
(
reg_id integer primary key,
student_id integer,
class_id integer
);
alter table only student_registrations
add constraint students_link
foreign key
(student_id) references students(student_id);
alter table only student_registrations
add constraint classes_link
foreign key
(class_id) references classes(class_id);
""".upper()
from pyparsing import Literal, Word, delimitedList \
, alphas, alphanums \
, OneOrMore, ZeroOrMore, CharsNotIn \
, replaceWith
skobki = "(" + ZeroOrMore(CharsNotIn(")")) + ")"
field_def = OneOrMore(Word(alphas,alphanums+"_\"':-") | skobki)
def field_act(s,loc,tok):
return ("<"+tok[0]+"> " + " ".join(tok)).replace("\"","\\\"")
field_def.setParseAction(field_act)
field_list_def = delimitedList( field_def )
def field_list_act(toks):
return " | ".join(toks)
field_list_def.setParseAction(field_list_act)
create_table_def = Literal("CREATE") + "TABLE" + Word(alphas,alphanums+"_").setResultsName("tablename") + \
"("+field_list_def.setResultsName("columns")+")"+ ";"
def create_table_act(toks):
return """"%(tablename)s" [\n\t label="<%(tablename)s> %(tablename)s | %(columns)s"\n\t shape="record"\n];""" % toks
create_table_def.setParseAction(create_table_act)
add_fkey_def=Literal("ALTER")+"TABLE"+"ONLY" + Word(alphanums+"_").setResultsName("fromtable") + "ADD" \
+ "CONSTRAINT" + Word(alphanums+"_") + "FOREIGN"+"KEY"+"("+Word(alphanums+"_").setResultsName("fromcolumn")+")" \
+"REFERENCES"+Word(alphanums+"_").setResultsName("totable")+"("+Word(alphanums+"_").setResultsName("tocolumn")+")"+";"
def add_fkey_act(toks):
return """ "%(fromtable)s":%(fromcolumn)s -> "%(totable)s":%(tocolumn)s """ % toks
add_fkey_def.setParseAction(add_fkey_act)
other_statement_def = ( OneOrMore(CharsNotIn(";") ) + ";")
other_statement_def.setParseAction( replaceWith("") )
comment_def = "--" + ZeroOrMore(CharsNotIn("\n"))
comment_def.setParseAction( replaceWith("") )
statement_def = comment_def | create_table_def | add_fkey_def | other_statement_def
defs = OneOrMore(statement_def)
print("""digraph g { graph [ rankdir = "LR" ]; """)
for i in defs.parseString(sampleSQL):
if i!="":
print(i)
print("}")
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